Bernd Hanewald, Franziska Behrens, Harald Gruppe, Gebhard Sammer, Bernd Gallhofer, Soeren Krach, Frieder Michel Paulus, Lena Rademacher and Jona Ruben Iffland
Numerous behavioural and neuroimaging studies have explored human cognitive processing of various rewards, such as food, monetary or social stimuli. Previous studies with patients suffering from schizophrenia (SZ) used incentive delay tasks with monetary rewards. Apart from slower reaction times in general in SZ, there were no differences in task performance between patients with schizophrenia and healthy controls (HC). Patients with schizophrenia have impaired social functioning and thus may have a disturbed sensitivity to social rewards. 54 schizophrenia patients and 54 matched healthy controls completed a reward paradigm (incentive delay task) with monetary (MID) and social stimuli (SID). Reaction times and hit rates were analysed using a three-way repeated measures ANOVA. Patients demonstrated increased reaction times in both, the MID and the SID tasks compared to health controls. Hit rates for healthy controls significantly increased in the MID task, however these results were not found in the SID task with increasing reward level. In both tasks SZ improved their performance as rewards increased. The present findings suggest that patients with SZ are capable to anticipate monetary or social rewards and use this anticipation to guide their behaviour. Extrapolated to social functioning, the capability to anticipate potential reward could be used in therapeutic interventions.